1. Field of the Invention
The present invention relates to an apparatus and method for performing Automatic Retransmission reQuest (ARQ) in a wireless communication system. More particularly, the present invention relates to an apparatus and method for performing ARQ in a wireless communication system using relay.
2. Description of the Related Art
In a wireless communication system, an error can occur in transmit/receive data depending on a channel state of a radio resource. A control and recovery technology for this error can be mainly divided into an Automatic Retransmission reQuest (ARQ) technique and a Forward Error Check (FEC) technique. The ARQ technique is a technique for transmitting a retransmission request to a transmit end for data lost in a receive end. The FEC technique is a technique for correcting an error for data lost in a receive end.
In the ARQ technique, if receive data is received without error, a receive end transmits an ACKnowledgement (ACK) message to a transmit end. If an error occurs in the receive data, the receive end transmits a Negative ACKnowledgement (NACK) message to the transmit end.
Thus, if the ACK message is received, the transmit end transmits new data to the receive end. If the NACK message is received, the transmit end retransmits data to the receive end in response to the NACK message.
A wireless communication system may include a relay service to provide a wireless channel to a Mobile Station (MS) located in an edge of a cell or a shadow area. When providing the relay service, the wireless communication system uses a Relay Station (RS) to relay data transmitted/received by a BS and an MS.
Therefore, a need exists for a method for performing ARQ using an RS for retransmitting of data in the wireless communication system using relay.